This invention relates to novel 2'-methylidenepyrimidine nucleosides possessing an excellent antitumor action, their pharmaceutical use and a method for producing said compounds.
Under the circumstances in which death due to cancer has increased, chemotherapy and immunotherapy in addition to surgical therapy have been widely conducted. In this connection, in chemotherapy, cytosine arabinoside, 5-fluorouracil and the like as antimetabolites, which are considered effective against acute leukemia, have been clinically used. However, the hitherto-known anticancer agents leave much to be desired in respect to therapeutic effect and involve various problems such as side effects. Thus, the development of excellent anticancer agents has been desired in various fields. Under such situations, the present inventors created 2'-deoxy-2'-methylidenecytidine and its pharmaceutically acceptable salts. However, since 2'-deoxy-2'-methylidenecytidine is inferior in solubility and its acid addition salts are unstable, they are unsatisfactory with respect to pharmaceutical production.